UK companies are seeking urgent help with Corporation Tax returns. HMRC no longer offers its free online CT600 filing tool. Many directors discover this change while preparing their annual accounts. They are unsure how to submit returns before strict HMRC deadlines.
HMRC permanently closed its free joint portal on 31 March 2026. Since 1 April 2026, limited companies must use commercial software to submit CT600 returns.
Why Businesses Are Struggling with the New Filing Process
The portal closure completely changes how small firms handle annual tax.
Directors log into Government Gateway expecting the old free form. Instead, they find that HMRC retired the service.
Many directors now ask two key questions:
- “How do I file my CT600 return now?”
- “Which software package do I need?”
Filing Corporation Tax is no longer quick or free. Small businesses must now buy recognized software or hire an accountant. This requirement adds unexpected costs for micro-entities, sole directors, dormant setups, and property holding firms.
Common Problems Directors Are Facing
HMRC and Companies House filings no longer share one portal. Directors must manage two separate workflows unless their software handles both. This extra step increases the risk of delayed or rejected submissions.
Outdated online tutorials and screenshots cause further confusion. Following old guides wastes valuable time as filing deadlines approach. Amending previous returns also creates hurdles. Companies cannot use the retired portal to fix past filings. They must now use compliant software or professional support.
What Businesses Should Do Now
Filing methods changed, but legal tax deadlines remained the same. Corporation Tax payments and CT600 filing dates still apply. Missing these dates triggers automatic HMRC penalties.
Follow these key steps to stay compliant:
- Verify your software: Ensure your tool supports CT600 forms and tax accounts.
- Keep record copies: Save PDFs of every submission for your company files.
- Plan: Allow extra time when using a new filing system.
How Lanop Can Help
UK tax compliance is moving toward total digital reporting. Companies must also adapt to new Companies House identity rules.
At Lanop Business and Tax Advisors, we help businesses stay compliant with complete confidence. Our chartered accountants prepare CT600 returns, format required accounts, and handle HMRC submissions.
Whether you need help choosing software or correcting past returns, Lanop protects your business from costly errors and late penalties.
